Transcarboxylase - (1) To determine the sequence of the 60 residue biotinyl peptide. (2) The trypsin peptides of the 12SH subunit will be finger printed to determine if there is a duplicating sequence in the peptide chain. Such duplication has previously been postulated to account for a variety of structures of the enzyme. (3) Efforts will be made to improve the specificity of the antibodies for the 12SH and 5SE subunits and for this 60 residue biotinyl peptide so that they may be used to study the rate of biotination of these subunits in pulse labeling experiments using intact cells. (4) Copper has been reported to be a component of transcarboxylase. The location of this metal in the various subunits and its role will be investigated. Pyruvate Carboxylase - (1) To elucidate the functional role of the two polypeptides of the enzyme from P. citronellolis. (2) To continue the binding studies with acetyl-CoA and with substrates with the avian liver, and with the yeast enzyme, particularly with the yeast enzyme after disensitization to acetyl-CoA activation as can be accomplished by treatment with trinitrobenzene sulfonate. (3) To establish the conditions for phosphorylation of pyruvate dehydrogenase in mitochondria and to compare the phosphorylation of this enzyme with that of pyruvate carboxylase.